Olson Technology OTPN-2000C - Manual (Page 5)

The receiver output power is also affected by the equalizer used.
The following chart assumes approximately 77 channels from 55MHz to 550MHz and
digital loading from 550MHz to 1,000MHz at -6dB. The RF levels indicated are for an
equivalent slope of 10dB with the actual levels measured at 547.25MHz.
Although the node operates at optical input levels as high as +3dBm, there is little CNR
improvement at levels above 0dBm. For optimum distortion performance, keep the
optical input at or below 0dBm. The Olson model OTOA-xxx optical attenuator is ideal
for this application. To lower the output level, the value of the “Forward Pad” should be
increased, but reducing output below +43dBmV at 547.25MHz by this method is not
recommended. If lower output is desired, the unit should be set for +43dBmV and an in-
line pad added to the RF output to reduce the output level. This maintains optimum
CNR performance. This also reduces the return gain if an OTPT-300 transmitter is used.
Unlike many optical nodes, the OTPN-2000C is designed to give full output perfor-
mance at optical input levels as low as -8dBm. Figure 2 shows the approximate CNR
performance at various input levels and channel loading. Performance can vary
depending upon fiber and laser performance so it is presented as a design aid only.
Olson recommends that the provided 15dB equalizer (OLEQ1G-15) always be used.
Other equalizer values will likely lead to reduced performance.